Torpedo depth steering control



April 18, 1961 s. JONES ETAL TORPEDO DEPTH STEERING CONTROL Filed June 28, 1954 s m V w DAMPED HYDROSTAT HYD ROSTAT S R m 0 T w NMY Eom VJW I SK 2% AH/ NP m" Ls ATTORNEY State z,9s0,04s

TORPEDO DEPTH STEERING CONTROL Leonard S. Jones and Stephen Kowalyshyn, Sharon, Pa., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Filed June'28, 1954, Ser. No. 439,949

' Claims. (Cl. 114-25) 2,980,048 Patented Apr. 18, 1961 2 erence whereby upon the loss of target contact the torpedo will resume searching at that depth at which target contact was lost rather than at the initial preset reference depth whereby to substantially increase the probabiliy of recontaining the target.

.And still a further object of the invention is to provide a torpedo depth steering system comprising an electrical synchro arrangement for providing output signals which are, respectively, a function of rate of change of torpedo depth and a combined function of rate of change of torpedo depth and torpedo depth error and wherein during a target search phase, the combined function signal is utilized for controlling the torpedo steering surface in accordance with the rate ofchange of torpedo depth and the deviation between instantaneous torpedo depth and a fixed reference depth and further wherein during a target attack phase the position error signal is removed from the the type including a pair of electrical synchros having their rotors angularly positioned as a function of depth and wherein one of the synchros has itsstator angularly positioned as a function of damped depth whereby the output of the last mentioned synchro will be a function ofthe rate-of change of torpedo depth, and wherein the other of the synchros has its stator angularly positioned to provide aireferencedepth whereby the output of this last mentioned synchro will be an error signal whose value is a function of the deviation between instantaneous torpedo depth and the-reference depth. The outputsignals of the synchros are applied to a depth systemservoamplifier for operating the torpedo control surfaces. Heretofore, torpedo depth control systems incorporating electrical synchro' arrangements of the type generally described above have been proposed. Such prior torpedo depth control systems had certain inherent disadvantages, however, the foremost of which were slow response in steering during the attack phase, owing to the fact that the position error signal,'which is a primary cause of slow response in steering, was active during the attack phase, and reduced probability of target recontact as a result of the torpedo resuming target search at the initial reference depth, after loss of target contact, rather than at that depth at which the last target signal was received.

The present invention avoids the disadvantages of the prior torpedo depth steering systems by'utilizing an electrical synchro arrangement, as described above, in such a manner that during the attack phase of the torpedo, the position error signal, which, .as heretofore, stated, is the primarycause of slow response in depth steering, is removed from the depth steering system and is independently employed to continuously reset the depth reference so as to cause the latter to correspond, at all times, to actual torpedo depth whereby upon the loss of target contact the torpedo will resume searching at that depth at which the last target signal wasreceived rather than returning to the initial reference depth, the probability of target reconta'ct thereby being substantially increased.

-, In accordance with the foreging, it is, an object of the present invention to provide an improved torpedo depth steering system.

Another object of the invention is to provide an im-,

proved torpedo depth controlsystem wherein a control signal which isa combined function of torpedo depth posi- H tion error and rate of change of torpedo depthserves to v control the torpedo steering surfaces during target search 7 periods, and wherein the position errorsignal is removed from the steering surface control circuit during periods 7 'of target contact whereby to provide for faster response in I I depth steering,

, "ll a-furthe'r object of the invention is to provide a torp d depth steering control system aszin the foregoing whereinduring periods of target .contactthe positionrror signalis independently utilized for resetting the depthrefsteering control circuit and is independently utilized for continuously resetting the reference depth so as to cause the latter to correspond at all times to instantaneous torpedo depth whereby upon loss of target contact the torpedo will resume searching at that depth at which target contact was lost rather than at the initial preset reference tion error and rate of change of torpedo depth, and an output voltage signal E2 which is a function of the rate of change in torpedo depth, a depth reset system 11, and a switching arrangement 12 for selectively applying the above mentioned depth control voltage signals to the depth system servo amplifier 13v and to the depth reset system 11. Synchro assembly 10 includes an electrical synchro generator 14, a first synchro control transformer 15 coupled,

to the output of generator 14, and a second synchro control transformer 16 also coupled to the output of generator 14, as shown. Generator 14 is electrically connected to a suitable AC. voltage supply, as shown, and has its stator 14s mechanically connected to a damped hydrostat' element, as indicated, whereby the stator will be angularly positioned in accordance with movement of the damped hydrostat bellows (not shown) and has its rotor 14rn1echanically connected to an undamped hydrostat elementfas indicated, whereby-'the'rotor'willbe angularly positioned in accordance with movement of the undampedhydrostat bellows (not shown), Stator 15s of synchro control transformerlS. is angularly positioned by v means of a reset'motor 17 controlled by the-depth reset 1 system 11, and rotor 15; of transfornierlS is angularly positioned in accordance with movement of the undar'nped v H hydrostat element, as indicated. 'The synchro generator 14 and synchro control transformer 15 are connected as shown in such manner that the output voltage signal E1 of the synchro assembly will be :a combined function of the deviation-20f torpedo depth from a given reference depth, which may be 'selectiyely preset'in the systernby operation ofthe resetmotor 17 to drive stator .159. 'of the .control transformer' 15 -to a 'desi'redxangular po'sition,and j rate of changeof torpedo depth,- whichi determines, the? instantaneous, differential angular displacement of the rotor" j14r and stator 1 14s, of synch ro .jgenerator 1'4 owing L; to diiferential moyements of the ,undamped' and clamped hydrostat bellows (notshown). The outputof'synchro generator 14 is applied to the control transformer 16 to obtain a voltage signal 134 which is a function of rate of change of torpedo depth. Switching arrangement 12, which operates in a manner hereinafter described to selectively applythe voltage signals to the depth reset system 11 and servo amplifier 13, includes a pair of single throw switch elements 18 and 19 and a pair of double throw switch elements 20 and 21, the movable contacts of which switch elements are simultaneously actuated by solenoid device 22, shown in its deenergized condition, controlled from the torpedo acoustic panel (not shown). A resistor type voltage divider 23 connected to the AC. "oltage source, as indicated, and including a movable pick-off 24 operated by a pair of up-down relays 25 and 26 controlled by the acoustic panel (not shown), serves to provide a voltage E-3, the value and phase of which relative to rate voltage E2, is determined by the position of pick-off 24 relative to its central or zero position. During an attack phase, voltage E-3 is, by operationof switching means 12, as will be described, applied in series with rate voltage E-2 to the servo amplifier 13 to control the operation of the depth steering system during the attack phase. Depth reset system 11 comprises a pair of vacuum tubes 27 and 28 which are connected, as shown, to form an amplifier which is inductively coupled to the 400 cyle operating voltage supply as at 29. The plate circuit of tube 28 includes a load resistor, as shown. Serially connected in the plate circuit of tube 27 is a coil 30 of a relay which operatively controls the position of a switch element 31, the latter serving to apply a DC. voltage from a source 32 to one or the other of a pair of series field windings included in reset motor 17 whereby to control the direction of rotation of the latter. is operatively connected to the solenoid 22 and is moved to its closed position upon energization thereof. A voltage 13-4, which is a function of the displacement of torpedo depth from set depth, is obtained during the attack phase by elfecting electrical subtraction of the rate signal E-2 from the combined position error and rate signal E -l. Thus, when a steering signal is inserted into the torpedo acoustic panel, not shown, relay 22 becomes energized and switch elements 18 and 19 close whereupon the combined signal E-l will be applied in series with rate signal E-2 and in opposition thereto to obtain the 400 cycle position error signal 13-4, the average value of which is a function the deviation of torpedo depth from set depth and the polarity of which indicates a too deep or too shallow sense. The position error voltage E-4 is amplified and its phase detected by the reset system 11 and theresultant signal is applied to operate the relay coil 30 A switch 33 in the D.C. circuit in a manner to cause reset motor 17 to reset position syn- I chro stator 15s in a direction to make E4 a minimum.

Switch elements 20 and 21 are electrically connected to the primary of a transformer 34, the secondary of which is electrically coupled to the servo amplifier 13, and act in a manner hereinafter described-to selectively couple the combinedsignal 134, during a search phase, or the-rate signal 15-2 in series with the incremental voltage E-3,

during an attack phase, to the servo amplifier 13. A pitch Operation of the present depth steering; system is as Prior to launching of the torpedo, an initial follows.

. reference depthis preset in the system by driving the stator 15s. of synehrolS to an angular position corresponding to the desiredpreset reference depth. During the torpedo search phasarelay 22 will, owingfto 'theabsence of a .targetsignal input to theacoustic panel, not shown, be deenrgi zed whereby switching arrangement 12 will be disposed in theposition shown wherein the voltage signal E-l, which as previously stated, is a combined function of displacement .of instantaneous torpedo depth from the 4% initial preset reference depth and rate of change in torpedo depth, will be applied in series with the pitch rate signal to the servo amplifier 13 through switch elements 20 and 21, which will be in their left hand position as seen in the drawing. Thus, the torpedo will search at the initial preset reference depth. Upon the establishment of target contact, relay 22 will be energized from the acoustic panel, not shown, whereby to close normally opened switch elements 18 and 19 and shift switch elements 20. and 21 to their right hand position. Energization of relay 22, because of reception of a target signal by the acoustic panel (not shown) also causes switch 33 in the reset motor voltage circuit to be closed. Closing of switch elements 18 and 19 acts to electrically connect the outputs of synchro 15 and synchro 16 in series opposition whereby the rate voltage E-2 will be electrically subtracted from the combined rate and position error voltage E-1 to obtain the position error voltage E-4 which is applied to the reset system. After amplification and phase detection the resultant signal serves to control the relay 30 in a manner to cause reset motor 17 to drive stator 15s of synchro 15 in a direction to make E-4 a minimum. Thus, the reference depth is constantly reset to correspond to instantaneous torpedo depth whereby upon loss of target contact the torpedo will resume searching at that depth at which the last target signal is received. Simultaneously, rate voltage 13-2 is applied in series with incremental voltage E3 to the servo amplifier owing to shifting of switch elements 20 and21 to their right hand position. Incremental voltage E-3 is varied by operation of the movable pick-off 24 under control of the up-down relays 25 and 26, the latter, as previously stated, being energized in accordance with the acoustic input to the torpedo, so as to cause the torpedo to assume varying rates of climb or dive and steer in depth toward the target. On loss of steering information, the acoustic panel, not shown, will cause the movable pick-off 24 to he stepped back to its zero position and de-energizing of relay 22 will result in the reinsertion of the depth position signal into the system thereby allowing the, torpedo to return to a horizontal search course under normal control at the new reference depth.

Obviously many modifications are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention maybe practiced otherwise than as specifically described herein. r r

What is claimed is:

1. In an acoustic torpedo depth steering system, means for generating electrical signals which are, respectively, a function of rate of change of torpedo depth and a combined function of rate of change of torpedo depth and depth error between torpedo position and i set depth,

means responsive to an electrical control signal for actuating the torpedo depth steering surfaces, means responsive to an electrical control signal for resetting set depth, and switch means operable-in one position for applying said combined function signal to the steering surface control means whereby to maintain the torpedomeans, being applied to said resetting means whereby to cause set depth to be continuously reset to correspond to instantaneous torpedo depth. it

2. The arrangement according to claim' I- wherein said first mentioned means comprises an electrical syn chro arrangement.

3. The arrangement according to claim 2 whereinflsaid synchro arrangement includes a synchro generator and a pair of synchro control transformers connected in. electical parallel to the output of said generator, means operatively connected to the, rotor of said'generatorfand the rotor of one of said transformers forangularly positioning said rotors as a function of torpedo depth, and

means operatively connected to the stator of the generator for angularly positioning said stator as a function of damped depth whereby the instantaneous differential angular displacement of the rotor and stator of the generator will be a function of rate of change of torpedo depth, the stator of said one transformer being operatively connected to said reset means and adapted to be angularly positioned as a function of the signal applied to the latter, the output of said one control transformer being said combined function signal and the output of the other control transformer being said rate signal.

4. The arrangement according to claim 3 wherein said resetting means comprises a reset motor for operatively driving the stator of said one control transformer, a relay for contolling the direction of rotation of said motor, and amplifier and phase detector means for controlling said relay in accordance with said depth error signal.

5. The arrangement according to claim 1 and means operable in the other position of said switching means for inserting incremental voltages in series with said rate signal and adapted to be varied in accordance with the incoming target signal whereby to effect steering of the torpedo in depth when said switching means is in said other position.

6. The arrangement according to claim 1 and means for inserting a pitch rate signal into said steering surface control means.

7. In an acoustic torpedo depth steering system, means for deriving electrical signals which are, respectively, a function of rate of change of torpedo depth, a combined function of rate of change of torpedo depth and depth error between torpedo position and set depth, and a function of depth error between torpedo position and set depth, resetting means responsive to an electrical control signal for resetting set depth, means responsive to an electrical control signal for actuating the torpedo depth steering surfaces, and means for selectively applying said combined function signal to said steering surface control means or said rate signal to said steering surface control means and said depth error signal to said resetting means.

8. The arrangement according to claim 7 and means for inserting a pitch rate signal into said steering surface control means.

9. The arrangement according to claim 7 and means for inserting incremental voltages into said steering suri 6 face controlmeans in series with said rate signal, said incremental voltages being adapted to be controlled in accordance with the target input signal whereby the torpedo may be steered in depth during periods of target contact.

10. In a torpedo depth control system, a first electrical synchro for providing a signal proportional to the displacement of the torpedo from a set depth determined by the angular position of the synchro stator relative to a fixed reference, a second synchro for providing a signal proportional to rate of change of torpedo depth, a servo amplifier, a variable voltage source for providing voltages having a polarity determined by the vertical position of the target relative to the torpedo, a reversible reset motor for varying the angular position of the stator of the first mentioned synchro for varying set depth, a first electrical circuit connected to said motor for'eifecting rotation of the latter in a direction determined by the polarity of the voltage applied to said circuit, a second electrical circuit including said synchros in series whereby'the output of said second circuit will be a voltage proportional to depth displacement error and depth rate, a third electrical circuit including the output of said first synchro in series with the output of said second synchro and in opposition thereto whereby the output of said third circuit will be the electrical difference of said synchro output signals, or a depth displacement error signal, a fourth electrical circuit including said second synchro output in series with said variable voltage source whereby the output of said fourth circuit will be the electrical difference of the instantaneous voltage of said source and said second synchro output voltage, and a relay for effecting selective connection of said circuits, said relay in its unenergized condition applying the output of said second circuit to said servo amplifier for search depth control, said relay in its energized condition simultaneously applying the output of said third circuit to said first circuit and the output of said fourth circuit to said servo amplifier whereby set depth will be continuously varied to correspond to the actual torpedo depth and' torpedo control surface deflection will be varied in accordance with the differential voltage output of said fourth circuit.

References Cited in the file of this patent UNITED STATES PATENTS Fischel Apr. 9, 1935 2,507,304- Hofstadter May 9, 1950 2,657,350 Rossire Oct. 27, 1953 

